Ideally your CPU is feeding your GPU and allowing it to be at max, while still fulfilling gaming logic to it's maximum.
No! Sorry, but that is incorrect!
Ideally, your CPU is feeding your GPU as much as your GPU calls for (and will ever call for!) as fast as the GPU can take it - while
still fulfilling all the demands of the operating system, all other running programs (like security), and all other system interrupts like storage and networking access, HID I/Os (human interface device - keyboard and mouse inputs) and whatever other multitasking demands are going on at that moment in time (like processing and handing off audio to the sound device).
Extra headroom is underutilized, wasted resources.
Wasted? No. Not unless you are talking about extreme amounts of extra headroom, and we're not. Having some resources in "reserve" is simply smart.
If your computer drew 250 watts, would you buy a 250W power supply? No, you would buy a PSU with extra headroom, like a nice 400W supply. Using a 1000W supply would be wasting resources - as in your budget resources.
If your CPU was capable of running without issues up to 80°C would you configure your cooling to maintain your CPU temp at 80°C. No, you would configure cooling to maintain the CPU well within its designed operating range.
Each step along the entire path must always be able to handle everything thrown at it without any delays (or overheating). And each step must be able to deliver to the next step everything the next step can take, as fast as it can accept it. That's where the balance comes in. It is not between two points, but between all points.
i would say if you have to create bottleneck and this should be only because of tight budget then ram speed and main disk drive.
I disagree with RAM "speed" unless you already have "
more RAM than you will ever need!" (whatever that means). That is, as a general rule (which means there are exceptions, of course), more RAM trumps faster RAM every day. I would much rather have 8GB of slow RAM than 4GB of fast RAM.
I do agree with you about disk drives. Sadly, many folks think SSDs only matter for boot and wake times. Not true. Since operating systems are very disk intensive, when the OS can finish tasks faster with a SSD, that frees up resources more quickly that can then be utilized elsewhere. So I would much rather take a slow SSD over the fastest hard drive any day of the week. And when it comes to "virtual memory" (RAM + Page File on the disk), more system RAM can mean fewer calls to the slow PF.
PSU is also interesting topic. You need to calculate how much wattage you really need, consider if you gonna overclock anything or not and pick proper 80+ certification.
Ummm, while I am all for picking an efficient PSU, 80+ certification has nothing to do with power demand. If your computer (CPU, graphics, RAM, drives, etc.) need 300W, they will pull from the PSU 300W regardless if the PSU is a 500W 70% efficient PSU or 750W 85% efficient PSU. All the 80+ Cert means is how much power
from the wall is wasted in the form of heat. The PSU is still going to pull from the wall what the computer needs, regardless the size or efficiency of the PSU (assuming the PSU is big enough). The difference is how much extra power will be pulled that will be wasted. Whatever the inefficiency amounts to has nothing to do with bottlenecks.
As far as the poll question, when it comes to gaming framerate bottlenecks, does everything boil down to the relationship between the CPU and GPU? No.